1. Field of the Invention
This invention relates to assay for an analyte and more particularly relates to an improved solid phase assay for Chlamydia.
2. Background of the Invention
The genus Chlamydiaceae includes two species, Chlamydia trachomatis and Chlamydia psittaci. Chlamydia trachomatis in its some 15 various strains is the etiologic agent for a number of human ocular and genital diseases, including trachoma, inclusion conjunctivitis, lymphogranuloma venereum, "nonspecific" or nongonococcal urethritis and proctitis. C. trachomatis infection is pervasive throughout the general population. It has been estimated, for instance, that C. trachomatis is accountable for several million cases per year of nongonococcal urethritis.
Since C. trachomatis mediated disease is widespread, a reliable, simple and inexpensive test for the organism's presence is highly desirable and of great importance so that proper treatment can be undertaken. The only serological test in current use is the microimmunofluorescence test. This test, however, requires that the strains of C. trachomatis be used as serological test antigen. In addition, the facilities for conducting this test are available in only a limited number of laboratories throughout the world. The test is very laborious, time consuming and difficult to perform.
Several immunoassay procedures for Chlamydia have been disclosed. PCT published application number WO 86/02733 discloses assay for various antigens, including Chlamydia which cause ocular infections. The assay includes immobilizing the antigen on a solid support by binding to a monoclonal antibody absorbed on the support, or the antigen is absorbed directly onto the solid support.
European Patent Application Number 0183383 discloses an assay for Chlamydia antigen which includes an isolation procedure in which the antigen is heated to a temperature of about 100.degree. C. to reduce nonspecific binding, then absorbed directly onto the support.
Rose, in U.S. Pat. No. 4,663,291 discloses treating a specimen suspected of containing Chlamydia organisms with a surfactant and a metal ion to release Chlamydia antigen and assay of the antigen by known methods including immobilization of the antigen on an absorbed antibody or absorption of the antigen directly onto the support.
Armstrong et al. in U.S. Pat. No. 4,497,899, discloses an immunoassay for Chlamydia antigen in which a sample suspected of containing Chlamydia organisms is lysed to release the antigen which is absorbed directly onto a solid support.
Sankolli et al., in the Journal of Immunological Methods discloses precoating microtiter wells with immunoglobulins to improve the binding of antibodies thereto leading to improved reproducibility of immunoassay for estradiol carried out in the wells.
In spite of the above disclosures, there yet remains a definite need for further improvement in assay for Chlamydia. It is toward fulfillment of this need that this invention is directed.